Our prime interests are the science and engineering of magnetic resonance (MR) imaging, and application in clinical practice. Currently we are developing techniques for imaging blood flow in large vessels (angiography) and in microvasculature (perfusion). These techniques are targeted for applications in cardiovascular diseases and neuro-functional mapping.

Cardiac MRI. Cardiovascular diseases is the No. 1 killer in the United States. Non-invasive diagnosis of cardiovascular diseases using MR would significantly advance patient care. For example, screening lesions in coronary arteries in their early stage prior to heart attack would provide a tremendous saving of lives. The challenge to imaging coronary arteries that supply blood to cardiac muscle is motion - cardiac contraction and respiration. This motion is difficult to predict by a model. We are developing techniques based on "imaging in the motion frame." The motion of the heart is sampled with navigator signals, which are processed in real-time and fed back to modify data acquisition accordingly, to eliminate motion artifacts. Substantial computer engineering and image processing are being integrated in this intelligent model-free navigator method.

Functional MRI. Human organ functions depend on and also affect blood supply. Accordingly, tissue perfusion provides assessment of organ function. Neuro-activation of the brain affects blood oxygenation level and perfusion rate. Neuro-function areas in the cortex can be mapped out by dynamic perfusion imaging synchronized to activation. MR brain mapping is one of the most exciting development in neuroscience, but the technology is still at its early stage. We are examining data acquisition strategies to improve signal-to-noise ratio and biophysics models to better understand the relation between activation and MR signal response.

MR Angiography. Our research work applies directly to clinical practice. We have developed non-invasive fluoroscopic MRA - MR digital subtraction angiography (MRDSA), and applied MRDSA to image vascular diseases in the lower extremity. To overcome the problem of the large longitudinal extend in the lower extremity (~ 100 cm, from aortic bifurcation to the feet), we developed a bolus chase MRDSA technique. Angiographic data acquisition follows the peak of the contrast passage (contrast bolus) from the proximal (aortic bifurcation) to distal location (feet), shortening scan time and minimizing contrast dose. Preliminary data confirmed that bolus chase MRDSA is a fast, accurate, and dose-minimized method, and bolus chase MRDSA is now a routine clinical tool at Cornell Medical Center, an non-invasive and economic alternative to x-ray Angiography.

For further information see Dr. Wang's lab